Cellular radiotelephones have become increasingly popular with users due in part to their convenience, greater area of coverage, and improved audio quality. In addition, increasing competition in the industry has created a climate where cellular radiotelephones have lost their stature as an instrument for the wealthy and have become affordable to the general public. As a result, greater numbers of people subscribe to cellular services and consequently carry subscriber-provided radiotelephones that may be borrowed, leased, or owned by the subscriber.
Due to the greater area of coverage and extended roaming agreements within the cellular industry, it has become practical and even necessary for subscribers to bring their radiotelephones with them while traveling. Thus, greater numbers of air travelers have their radiotelephones while flying. In accordance with current methodologies, an air traveler may be able to place a call from a subscriber-provided radiotelephone while the aircraft is on the ground prior to take-off and after landing, however, this capability does not extend to in-flight use.
The use of conventional cellular radiotelephones in-flight has not been allowed in part because the aircraft is flying through multiple cells supported by land-based cellsites. These land-based cellsites would most likely instruct radiotelephones to transmit at high power levels. These high power levels pose a danger of interference with standard aircraft transmissions and control.
To allow passengers in-flight to communicate with someone on the ground, many aircraft are equipped with air-to-ground communications systems. One currently existing system, known as Airfone.RTM., uses a network of ground stations to provide telecommunications for a plurality of aircraft. Each ground station conducts communications with passengers on aircraft within its range, on specific FCC allocated radiofrequency channels, using one or more pilot channels and up to 31 additional voice channels that accompany each pilot channel. The pilot channels carry information necessary for an aircraft to select an optimal ground station as determined by its position and flight direction, and subsequently to utilize unoccupied voice channels associated with that ground station. Following ground station selection, the voice channels carry encoded conversations between the aircraft, through the selected ground station, to called numbers on landline networks.
Two types of telephone systems, cordless and corded, have been utilized inside the aircraft in air-to-ground communication systems. One telephone system includes cordless telephones located at paystations within the passenger cabin of the aircraft. In this type of telephone system, the passenger leaves his seat and walks to a paystation. Once the passenger is at the paystation, the passenger inserts his or her credit card into the paystation to activate the telephone system. The passenger may then return to his seat with the cordless telephone to place the call, while leaving his credit card in the paystation for validation and billing. Upon return of the cordless telephone, the passenger retrieves this credit card. While providing the passenger with the freedom to take the telephone back to his seat, this system may suffer from inferior signal quality. Additionally, passengers leaving their seats to retrieve telephones may increase the quantity of unrestrained passengers moving about in the cabin, which raises safety concerns. If the passenger is unable to leave his or her seat, the flight attendant could obtain the passenger's credit card, insert it in the paystation, and deliver the telephone to the passenger. However, this imposes additional responsibilities on already busy flight attendants. In addition, many credit card holders feel uncomfortable about relinquishing their credit card to someone else.
Another type of air-to-ground communication system utilizes corded telephones. These telephones are wired into the seatback of one of a set of two or three seats. Instead of the passenger moving to the paystation, the paystation has been moved to the passenger. This system results in better signal quality of the call. In addition, this system results in added passenger convenience and safety. However, a disadvantage of the corded telephone is the significant expense to wire up the seatbacks, as well as to functionally maintain the large number of corded telephones.
While the previously discussed systems provide a method for passengers to have air-to-ground communications during a flight, these systems do not support seat-to-seat communications. Seat-to-seat communications may be desired if two passengers who are not sitting together would like to speak with each other but are unable to move about in the cabin. In addition, the two passengers may want to jointly teleconference with someone at a ground site. Thus, there is a need for an improved method of providing telecommunication services to aircraft passengers that cost-effectively provides reliable signal quality, greater convenience to the passenger, and increased calling options.